The first reaction is usually to collect the animal and take it back to a lab for testing to ensure it is what it appears — it could belong to a new species or an existing one. But this practice of removing specimens from the wild could have dire consequences for threatened species.

"Because these populations are very small and often isolated, they are incredibly sensitive to over-collecting," says Ben Minteer, an environmental ethicist at Arizona State University. He and colleagues in Arizona and England are pleading in this week's issue of Science for biologists to use alternate collection methods for vulnerable species identification. "Combine the understandable impulse to confirm something really important — such as that a species is not, in fact, extinct — with the sensitivity of a population to collection and you've got a potentially significant conservation issue," he said in a news release.